Comparison of antipsychotic medication effects on reducing violence in people with schizophrenia

Background Violence is an uncommon but significant problem associated with schizophrenia. Aims To compare antipsychotic medications in reducing violence among patients with schizophrenia over 6 months, identify prospective predictors of violence and examine the impact of medication adherence on reduced violence. Method Participants (n=1445) were randomly assigned to double-blinded treatment with one of five antipsychotic medications. Analyses are presented for the intention-to-treat sample and for patients completing 6 months on assigned medication. Results Violence declined from 16% to 9% in the retained sample and from 19% to 14% in the intention-to-treat sample. No difference by medication group was found, except that perphenazine showed greater violence reduction than quetiapine in the retained sample. Medication adherence reduced violence, but not in patients with a history of childhood antisocial conduct. Prospective predictors of violence included childhood conduct problems, substance use, victimisation, economic deprivation and living situation. Negative psychotic symptoms predicted lower violence. Conclusions Newer antipsychotics did not reduce violence more than perphenazine. Effective antipsychotics are needed, but may not reduce violence unrelated to acute psychopathology. Declaration of interest J.W.S., M.S.S., RAND., T.S.S. and H.R.W. have received research support from Eli Lilly, M.S.S. has received consulting and educational fees from AstraZeneca, Bristol-Myers Squibb, Eli Lilly and Pfizer. T.S.S. has received consulting fees from Janssen, GlaxoSmithKline and Bristol-Myers Squibb. J.P.McE. has received research funding from AstraZeneca, Eli Lilly, Janssen and Pfizer, consulting or advisory board fees from Pfizer and Bristol-Myers Squibb, and lecture fees from Janssen and Bristol-Myers Squibb. J.A.L. has received research funding from AstraZeneca, Bristol-Myers Squibb, GlaxoSmithKline, Janssen and Pfizer, and consulting and education fees from AstraZeneca, Bristol-Myers Squibb, Eli Lilly, Forest, GlaxoSmithKline, Janssen, Novartis, Pfizer and Solvay.